Promised Neverland. Why didn't humans drove the Demons into extinction?

[ammatrax]

From what I know, Humans have fought back the demons and got good at it to the point that they just hunt demons for fun. Based on what we did with other Fauna and Flora throughout our history. Why didn't humans just kill them off from the face of the planet? especially when the demons are natural predators of Humans.

 

[bigtiddyoneesan]

@ammatrax
There's a flashback around chapter 141 of the manga.

Spoilers (I guess):

Spoiler

>humans and demons constantly at war 1,000 years ago
>Julius Ratri (leader of the humans or something) wants to end the fighting because he's about to die in battle
>Julius sells out his comrades and makes a deal with the demon god
>deal results in the world being split into two worlds, one for humans, one for demons
>hilarity ensues

Julius was a little butt baby and refused to fight for jiyuu. If he hadn't made the deal, one side would've wiped out the other.

 

[BzzBzz]

> Why didn't humans drove the Demons into extinction?

Chapter 1: Manga starts, reasons for the war explained.
Chapter 2: One side wipes another one. Happy ending.

Do you prefer this scenario?